1. Field of the Invention
This invention relates to a method of securing the magnets of a revolving electric machine in position. More particularly, this invention relates to a method of rigidly securing magnets to the yoke of the stator of an electric motor (hereinafter referred to as motor) or that of the rotor of a magnet generator (fly-wheel magnet generator), which method may find a wide variety of applications in the field of manufacturing motors to be used for the electric equipment of automobiles.
2. Related Art Statement
Electric motors comprising a plurality of magnets arranged annularly and peripherally at regular intervals along the inner peripheral surface of a hollow cylindrical yoke and rigidly secured in position by means of a hollow cylindrical magnet cover press-fitted to the inner peripheral surfaces of the magnets are widely used as the electric equipment of automobiles.
As a conventional magnet securing method such as the above kind, there is a magnet cover built-in method for a permanent magnet motor shown in Japanese Patent Publication No. 5-59661. With the disclosed method of arranging a built-in type magnet cover, a hollow cylindrical yoke having openings at the opposite ends is used in an ingenious manner. More specifically, magnets are arranged annularly and peripherally at regular intervals along the inner peripheral surface of the yoke and supported by a magnets-aligning jig introduced from one of the openings of the yoke, and a magnet cover is introduced from the other opening of the yoke and press-fitted to the inner peripheral surfaces of the group of magnets.
However, with the above described method, if a yoke with a closure wall end is used, the jig or the magnet cover cannot be introduced from the side of the closure wall of the yoke and it is impossible to arrange the magnet cover within the yoke.
This problem may be bypassed by providing the closure wall of the yoke with an opening, through which the jig can be introduced to align and support the magnets. Then, however, the stator of the motor has to be provided with a sealing means for hermetically sealing the opening that is used to introduce the jig in order to align the magnets. Otherwise, the motor will be devoid of water-resistance.